.input {
  border: 3px solid green
}

/* react-transition-group */
.fade-enter, .fade-exit-done {
  opacity: 0;
}
.fade-enter-active {
  opacity: 1;
  transition: opacity .5s;
}
.fade-exit, .fade-enter-done {
  opacity: 1;
}
.fade-exit-active {
  opacity: 0;
  transition: opacity .5s;
}